Photoresist Employing Photodimerization Chemistry and Method for Manufacturing Organic Light Emitting Diode Display Using the Same

ABSTRACT

A highly fluorinated photoresist employing a photodimerization chemistry and a method for manufacturing an organic light emitting diode display using the same. The photoresist includes a copolymer that is made from two different monomers. When the copolymer is used as a photoresist, the photoresist has the characteristic that it becomes insoluble when exposed to an ultraviolet light having a wavelength of 365 nm.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of Korea Patent Application No.10-2012-0138223 filed on Nov. 30, 2012, which is incorporated herein byreference in its entirety.

BACKGROUND

1. Field of the Invention

The present disclosure relates to a highly fluorinated photoresistemploying a photodimerization chemistry and a method for manufacturingan organic light emitting diode display using the same.

2. Discussion of the Related Art

Nowadays, various flat panel display devices are developed forovercoming many drawbacks of the cathode ray tube such as heavy weightand bulk volume. The flat panel display devices include the liquidcrystal display device (or LCD), the field emission display (or FED),the plasma display panel (or PDP) and the electroluminescence device (orEL).

FIG. 1 is a plane view illustrating the structure of the organic lightemitting diode display (or ‘OLED’) having active switching elements suchas thin film transistors according to the related art. FIG.2 is a crosssectional view illustrating the structure of the OLED along to thecutting line of I-I″ in FIG. 1 according to the related art.

Referring to FIGS. 1 and 2, the OLED display comprises a thin filmtransistor (or ‘TFT’) substrate having the thin film transistors ST andDT and an organic light emitting diode OLED connected to and driven bythe thin film transistors ST and DT, and a cap ENC joining the TFTsubstrate with an organic adhesive POLY (not shown) therebetween. TheTFT substrate includes a switching thin film transistor ST, a drivingthin film transistor DT connected to the switching thin film transistorST, and an organic light emitting diode OLED connected to the drivingthin film transistor DT.

On a transparent substrate SUB, the switching thin film transistor ST isformed where a gate line GL and a data line DL cross each other. Theswitching thin film transistor ST selects the pixel which is connectedto the switching thin film transistor ST. The switching thin filmtransistor ST includes a gate electrode SG branching from the gate lineGL, a semiconductor channel layer SA overlapping with the gate electrodeSG, a source electrode SS and a drain electrode SD. The driving thinfilm transistor DT drives an anode electrode ANO of the organic lightemitting diode OD disposed at the pixel selected by the switching thinfilm transistor ST. The driving thin film transistor DT includes a gateelectrode DG connected to the drain electrode SD of the switching thinfilm transistor ST, a semiconductor channel layer DA, a source electrodeDS connected to the driving current line VDD, and a drain electrode DD.The drain electrode DD of the driving thin film transistor DT isconnected to the anode electrode ANO of the organic light emitting diodeOD.

As one example, FIG. 2 shows the thin film transistor of top gatestructure. In this case, the semiconductor channel layers SA and DA ofthe switching thin film transistor ST and the driving thin filmtransistor DT are firstly formed on the substrate SUB and the gateinsulating layer GI covering them and then the gate electrodes SG and DGare formed thereon by overlapping with the center portion of thesemiconductor channel layers SA and DA. After that, at both sides of thesemiconductor channel layers SA and DA, the source electrodes SS and DSand the drain electrodes SD and DD are connected thereto through contactholes penetrating an insulating layer IN. The source electrodes SS andDS and the drain electrodes SD and DD are formed on the insulating layerIN.

In addition, at the outer area surrounding the display area where thepixel area is disposed, a gate pad GP formed at one end of the gate lineGL, a data pad DP formed at one end of the data line DL, and a drivingcurrent pad VDP formed at one end of the driving current line VDD arearrayed. A passivation layer PAS is disposed to cover the upper wholesurface of the substrate SUB having the switching and the driving thinfilm transistors ST and DT. After that, the contact holes are formed toexpose the gate pad GP, the data pad DP, the driving current pad VDP andthe drain electrode DD of the driving thin film transistor DD. Over thedisplay area within the substrate SUB, a planar layer PL is coated. Theplanar layer PL makes the roughness of the upper surface of thesubstrate SUB in much smoother condition, for coating the organicmaterials composing the organic light emitting diode on the smooth andplanar surface condition of the substrate SUB.

On the planar layer PL, the anode electrode ANO is formed to connect thedrain electrode DD of the driving thin film transistor DT through one ofthe contact holes. On the other hand, at the outer area of the displayarea not having the planar layer PL, formed are a gate pad electrodeGPT, a data pad electrode DPT and a driving current electrode VDPTconnected to the gate pad GP, the data pad DP and the driving currentpad VDP, respectively, exposed through the contact holes. On thesubstrate SUB, a bank BA is formed covering the display area, exceptingthe pixel area. Finally, a spacer SP may be formed over some portion ofthe bank BA.

A cap ENC is joined to the TFT substrate. In that case, it is preferablethat the TFT substrate and the cap ENC are completely sealed by havingan organic adhesive between them. The gate pad electrode GPT and thedata pad electrode DPT are exposed and may be connected to externaldevices via the various connecting means.

As the needs for the organic light emitting diode display increase, andmore advanced manufacturing technologies are developing, thetechnologies for the high resolution and large area organic lightemitting diode displays has become underdeveloped. Until now, there aresome methods for forming organic light emitting diodes on a large glasssubstrate, i.e., the fine metal mask (or ‘FMM’) patterning technology,the ink jetprinting technology, and the laser patterning technology. Asan alternative method for manufacturing a large area organic lightemitting diode display, a method for depositing one large white organiclight emitting diode layer with a patterned color filter layer can alsobe used.

Using these patterning technologies or methods, it is possible tomanufacture an organic light emitting diode display having large areaand high resolution. However, the production yields and/or costs are notacceptable for mass production. In order to manufacture the pixel areaof high resolution on a large area substrate, the most reasonable methodis the photolithography method. There is still a critical problem forusing the photolithography technology when patterning the organic lightemitting materials. For example, the organic light emitting material canbe easily damaged by the photoresist itself and the solvent used fordeveloping and/or removing the photoresist.

SUMMARY

In order to overcome the above mentioned drawbacks, the purpose of thepresent disclosure is to suggest a highly fluorinated photoresist whichis less interactive with organic light emitting materials, and a methodfor manufacturing an organic light emitting diode display using the samephotoresist. Another purpose of the present disclosure is to suggest ahighly fluorinated photoresist which is changing the solubility by thephotodimerization reaction of anthracene to minimize the damage of theorganic light emitting diode material, and a method for manufacturing anorganic light emitting diode display using the same photoresist.

In one embodiment, a copolymer for a photoresist is disclosed. Thecopolymer is formed by a process that includes providing a first monomerrepresented by formula (1) and a second monomer represented by formula(2)

where x:y is a ratio of the first monomer to the second monomer and x:yis selected from the range of x:y=1:0.1 to x:y=1:1. The copolymer isformed from the first monomer and the second monomer. When the copolymeris used as a photoresist, the photoresist has the characteristic that itbecomes insoluble when exposed to an ultraviolet light having awavelength of 365 nm.

In one embodiment, x:y is selected from the range of x:y=1:0.19 tox:y=1:0.77. In some embodiments, x:y can be 1:0.19, x:y can be 1:0.25,x:y can be 1:0.38, x:y can be 1:0.58, or x:y can be 1:0.77.

In one embodiment, the present disclosure includes a method formanufacturing an organic light emitting diode display comprising:forming an electrode on a substrate; depositing an organic lightemitting layer on the electrode; depositing a photoresist on the organiclight emitting layer, the photoresist including the above mentionedcopolymer; patterning the photoresist into a patterned photoresist byexposing the photoresist to an ultraviolet light through a mask;patterning the organic light emitting layer into a patterned organiclight emitting layer using the patterned photoresist; and stripping thepatterned photoresist.

In one embodiment, the present disclosure includes a method formanufacturing an organic light emitting diode display comprising:forming an electrode on a substrate; depositing a photoresist on theelectrode, the photoresist including the above mentioned copolymer;patterning the photoresist into a patterned photoresist by exposing thephotoresist to an ultraviolet light through a mask; depositing anorganic light emitting layer on the patterned photoresist and theelectrode; and removing the patterned photoresist and portions of theorganic light emitting layer on the patterned photoresist.

In one embodiment, the ultraviolet light has a wavelength of 365 nm. Inone embodiment, the photoresist is patterned with a fluorinated solvent.

The highly fluorinated photoresist according to the present disclosurehas the characteristics in which its solubility is changed by thephotodimerization reaction of anthracene and less interaction withorganic light emitting materials. As it has no anthracence, any strongacid material is not be formed when developing the photoresist. As aresult, by using the highly fluorinated photoresist less interactionwith the organic light emitting materials, it is possible to manufacturethe organic light emitting diode display having the high resolution onthe large area substrate. Furthermore, in the method for manufacturingthe organic light emitting diode display according to the presentdisclosure, as it is possible to use the same material when developingthe photoresist and removing the photoresist, the manufacturing processcan be simple, the cost may be reduced, and the production yield may behigh.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this specification, illustrate embodiments of the invention andtogether with the description serve to explain the principles of theinvention.

In the drawings:

FIG. 1 is the plane view illustrating the organic light emitting diodedisplay using the thin film transistor according to the related art.

FIG. 2 is the cross sectional view illustrating the structure of theorganic light emitting diode display cutting along the line I-I′ in FIG.1, according to the related art a back light unit generating thecollimated light beam using a collimation lens.

FIG. 3 is a schematic view illustrating steps for synthesizing a highlyfluorinated photoresist according to the present disclosure.

FIG. 4 is a schematic view illustrating the change of the soluabilitycharacteristics of the highly fluorinated photoresist by the wavelengthsof the ultralight according to the present disclosure.

FIGS. 5A to 5D are cross sectional views illustrating a method formanufacturing an organic light emitting diode display according to thefirst embodiment of the present disclosure.

FIGS. 6A to 6D are cross sectional views illustrating a method formanufacturing an organic light emitting diode display according to thesecond embodiment of the present disclosure.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

Embodiments of the present disclosure are explained herein by referencesto the figures. Like reference numerals designate like elementsthroughout the detailed description. However, the present disclosure isnot restricted by these embodiments but can be applied to variouschanges or modifications without changing the technical spirit. In thefollowing embodiments, the names of the elements are selected byconsidering the easiness for explanation so that they may be differentfrom actual names.

At first, a novel highly fluorinated photoresist will be explained. Thehighly fluorinated photoresist according to the present disclosureincludes a copolymer that is synthesized from two monomers,3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10-Heptadecafluorodecyl Methacrylate(FDMA) and 6-(anthracene-9-yl)hexyl methacrylate (AHMA):

where x:y is a ratio of monomer FDMA to monomer AHMA used insynthesizing the co-polymer. In one embodiment, x:y is selected from therange of x:y=1:0.1 to x:y=1:1, as explained below. In one embodiment,FDMA has a molecular weight of 532.19, and AHMA has a molecular weightof 346.46.

In one embodiment the resulting photoresist co-polymer formed from FDMAand AHMA is a statistical or random co-polymer and can be representedwith the following chemical formula, where r refers to the random natureof the co-polymer:

Hereinafter, referring to FIG. 3, we will explain an example forsynthesizing the highly fluorinated photoreist copolymer according tothe present disclosure. The following description is just one example ofsynthesizing a copolymer so that the present disclosure is not limitedby this example. FIG. 3 is a schematic view illustrating steps forsynthesizing a highly fluorinated photoresist according to the presentdisclosure.

SYNTHESIZING EXAMPLE Synthesizing of the Represented by the Formula 1

1) The synthesizing of 6-(anthracen-9-yl)hexan-1-ol (AHOH).

5-Hexenyl acetate (2.00 g, 14.06 mmol) and 9-Borabicyclo[3.3.1]nonane(0.5M solution in THF) (9-BBN) (25.21 g, 14.06 mmol) were put into afirst flask of 250 ml. A stirring process was then performed for 3 hoursat room temperature under N₂ gas condition. After putting 3M NaOHsolution (9.14 ml), 9-Bromoanthracene (3.30 g, 12.80 mmol), and THFanhydrous (25 cm³) into a second flask of 100 ml, a bubbling process wasperformed three times. After that,Tetrakis(triphenylphosphine)palladium(0) (Pd(PPh3)4) (0.44 g, 0.38 mmol)was added into the second flask and the bubbling process was performedthree times again. The mixture of the 5-Hexenyl acetate and the 9-BBN ofthe first flask was put together with the mixture of the second flask,under N₂ gas condition, to perform a reaction process under atemperature of 85 C for 18 hours. After the reaction, the temperaturewas lowered to room temperature , and the reaction was completed byadding distilled water (22.85 ml) and the toluene (57.14 ml). Afterthat, using HCl, a neutralization process was performed. With EA andbrine, the work-up process was performed to the neutralized product.Using MgSO₄, moisture was removed. After purifying this compositingmaterial, using Hexane (30 cm³) and toluene (10 cm³), a recrystalizationprocess was performed. After filtering and drying the material in thevacuum oven, a yellow powder synthesized (or ‘composition’) material(2.78 g, 71%) was acquired.

2) The synthesizing of AHMA.

The synthesized 6-(anthracen-9-yl)hexan-1-ol (AHOH) (2.78 g, 10.00mmol), 4-Dimethylaminopyridine (DMAP) (1.830 g, 14.98 mmol),2,6-Di-Tert-butyl-4-methylphenol (BHT) (polymerization inhibitor, 0.01g), Methacrylic anhydride (3.079 g, 1997 mmol), and DCM anhydrous (30cm³) were put into a flask of 250 ml. A stirring process was thenperformed for 4 hours under room temperature. After that, MeOH (1 cm3)was added, and a stirring process was performed again for 1 hour. Afterpurifying the composition material, an oil type synthesized material(1.94 g, 56%) having a light yellow color was acquired.

3) The synthesizing of the FDMA-AHMA co-polymer.

FDMA (4.00 g) and AHMA (0.65 g) were put into a tube of 25 cm³.α,α,α-trifluorotoluene (5.00 cm³) and purified AIBN (0.048 g) wereadded. After sealing the tube, using a vacuum pump and N₂ gas, a N₂substitution process was performed through three freeze-thaw cycles.After nitrogen substitution, under N₂ gas condition, the solution wasstirred for 12 hours under a temperature of 72 degrees C. After that, aprecipitation process was performed using Hexane and the solvent wasremoved in a vacuum oven, there resulting in a white powder synthesizedmaterial (3.834 g).

In other embodiments, the FDMA-AHMA co-polymer was synthesized using thesame fixed mass of FDMA (4.00 g) but with different masses of AHMA, suchas with AHMA masses of 0.50 g, 1.00 g, 1.50 g and 2.00 g. The followingtable illustrates different combinations of FDMA and AHMA used insynthesizing the FDMA-AHMA co-polymer:

TABLE 1 molecular ratio of FDMA mass (g) AHMA mass (g) FDMA to AHMA 4 g0.5 g 1:0.19 4 g 0.65 g  1:0.25 4 g 1.0 g 1:0.38 4 g 1.5 g 1:0.58 4 g2.0 g 1:0.77

Each of the FDMA-AHMA copolymers from Table 1 was tested and found tohave the same photo characteristics. Specifically, the photocharacteristics of the co-polymer used as the novel synthesized highlyfluorinated photoresist is shown in FIG. 4. FIG. 4 is a schematic viewillustrating the change of the soluability characteristics of the highlyfluorinated photoresist by the wavelengths of ultraviolet lightaccording to the present disclosure. Referring to FIG. 4, just afterbeing synthesized, the novel highly fluorinated photoresist was solublein hydrofluoroethers (HFEs). However, after being exposed to anultraviolet light of 365 nm wavelength, the structure of the highlyfluorinated photoresist was changed so that it became insoluble inhydrofluoroethers (HFEs).

Hereinafter, referring to FIGS. 5A to 5D, a method for manufacturing anorganic light emitting diode display according to the first embodimentof the present disclosure is now explained. FIGS. 5A to 5D are crosssectional views illustrating a method for manufacturing an organic lightemitting diode display according to the first embodiment of the presentdisclosure.

On a substrate SUB, an anode electrode ANO is deposited. For the case ofthe active type organic light emitting diode display, as shown in FIGS.1 and 2, the thin film transistor may first be formed. After that, theanode electrode ANO is formed to connect to the drain electrode of thethin film transistor. As the present embodiment is related to the methodfor patterning the organic light emitting material, the explanation forother elements of the display including thin film transistor may not bementioned in detail.

As shown in FIG. 5A, on the anode electrode ANO, an organic lightemitting material is deposited to form an organic light emitting layerEL. On the organic light emitting layer EL, the highly fluorinatedphotoresist PR is deposited. After positioning a mask MA having apre-determined mask pattern over the photoresist PR, a first ultravioletlight UV1 having a wavelength of 365 nm is radiated over the mask MA.Then, according to the pattern of the mask MA, some portions of thephotoresist PR are exposed to the first ultraviolet light UV1 and otherportions of the photoresist PR are not affected by the first ultravioletlight UV1. Due to the characteristics of the highly fluorinatedphotoresist PR, the portions of the photoresist PR exposed by the firstultraviolet light UV1 change into an insoluble photoresist IPR. On thecontrary, the portions not exposed by the first ultraviolet light UV1are unchanged and remain as the soluble photoresist SPR.

After exposure, by developing the photoresist PR with a fluorinatedsolvent such as hydrofluoroethers, the soluble photoresist SPR may beremoved. However, the insoluble photoresist IPR remains on the organiclight emitting layer EL, as shown in FIG. 5B.

Using the insoluble photoresist IPR as a mask, the organic lightemitting layer EL is patterned. Thus, the organic light emitting layerEL can be formed into the same pattern as the insoluble photoresist IPR,as shown in FIG. 5C.

After that, using a chemical stripper, the insoluble photoresist IPR maybe removed, as shown in FIG. 5D. In the photolithography processaccording to the first embodiment of the present disclosure, theinsoluble photoresist IPR is formed on the organic light emitting layerEL by the pattern of the mask MA and the organic light emitting layer ELis patterned according to the shape of the insoluble photoresist IPR.

Hereinafter, referring to FIGS. 6A to 6D, we will explain a method formanufacturing an organic light emitting diode display according to thesecond embodiment of the present disclosure. FIGS. 6A to 6D are crosssectional views illustrating a method for manufacturing an organic lightemitting diode display according to the second embodiment of the presentdisclosure.

On a substrate SUB, an anode electrode ANO is deposited. For the case ofthe active type organic light emitting diode display, as shown in FIGS.1 and 2, the thin film transistor may first be formed. After that, theanode electrode ANO is formed to connect to the drain electrode of thethin film transistor. As the present embodiment is related to the methodfor patterning the organic light emitting material, the explanation forother elements of the display including thin film transistors may not bementioned in detail.

As shown in FIG. 6A, on the anode electrode ANO, the highly fluorinatedphotoresist PR according to the present disclosure is deposited. Afterpositioning a mask MA having a pre-determined mask pattern over thephotoresist PR, a first ultraviolet light UV1 having wavelength of 365nm is radiated over the mask MA. Then, according to the pattern of themask MA, some portions of the photoresist PR are exposed to the firstultraviolet light UV1, and other portions of the photoresist PR are notinfluenced by the first ultraviolet light UV1. Due to thecharacteristics of the photoresist PR according to the presentdisclosure, the portions exposed by the first ultraviolet light UV1 maybe changed into the insoluble photoresist IPR. On the contrary, theportions not exposed by the first ultraviolet light UV1 are not changedand remain as the soluble photoresist SPR.

After exposure, by developing the photoresist PR with a fluorinatedsolvent such as hydrofluoroethers, the soluble photoresist SPR may beremoved. However, the insoluble photoresist IPR remains on the organiclight emitting layer EL, as shown in FIG. 6B.

By depositing an organic light emitting material over whole surface ofthe substrate SUB and the insoluble photoresist IPR, an organic lightemitting layer EL can be formed, as shown in FIG. 6C. Even though it isnot shown in the figures, the insoluble photoresist IPR may have thereversed tapered shape at its edges.

After depositing the organic light emitting layer EL, the insolublephotoresit IPR is stripped out. At the same time, portions of theorganic light emitting layer EL deposited on the soluble photoresist IPRare also removed. As a result, the portions of the organic lightemitting layer EL contacting the anode electrode ANO remain so that thepattern is completed, as shown in FIG. 6D. In the second embodiment ofthe present disclosure, a highly fluorinated solvent such ashydrofluoroethers can be used when developing the photoresist.Furthermore, in the photolithography process according to the secondembodiment of the present disclosure, the exposed portions of thephotoresist IPR exposed by the mask MA remain, and the organic lightemitting layer EL is formed into a pattern that is the reverse of theinsoluble photoresist IPR.

In the first and second embodiments of the present disclosure, bypatterning the organic light emitting layer using the highly fluorinatedphotoresist, the method for manufacturing the organic light emittingdiode display is explained. The organic light emitting material mayinclude materials emitting red, green or blue color light or includematerial emitting white color light. For example, for the case of thewhite color light, a color filter is deposited on the organic lightemitting material layer, and the color filter may be patterned using thehighly fluorinated photoresist according to the present disclosure.

The manufacturing method according to the present disclosure preventsthe organic light emitting material from being damaged during thepatterning process by patterning the photoresist without using a photoacid generator (PAG). Additionally, the photoresist according to thepresent disclosure can be used not only for patterning the organic lightemitting material but also for patterning the other layers.

While the embodiment of the present invention has been described indetail with reference to the drawings, it will be understood by thoseskilled in the art that the invention can be implemented in otherspecific forms without changing the technical spirit or essentialfeatures of the invention. Therefore, it should be noted that theforgoing embodiments are merely illustrative in all aspects and are notto be construed as limiting the invention. The scope of the invention isdefined by the appended claims rather than the detailed description ofthe invention. All changes or modifications or their equivalents madewithin the meanings and scope of the claims should be construed asfalling within the scope of the invention.

What is claimed is:
 1. A copolymer of a photoresist formed by theprocess comprising: providing a first monomer represented by formula (1)and a second monomer represented by formula (2)

and forming the copolymer from the first monomer and the second monomer,where x:y is a ratio of the first monomer to the second monomer and x:yis selected from the range of x:y=1:0.1 to x:y=1:1.
 2. The copolymeraccording to claim 1 wherein x:y is selected from the range ofx:y=1:0.19 to x:y=1:0.77.
 3. The copolymer according to claim 1 whereinx:y is 1:0.19.
 4. The copolymer according to claim 1 wherein x:y is1:0.25.
 5. The copolymer according to claim 1 wherein x:y is 1:0.38. 6.The copolymer according to claim 1 wherein x:y is 1:0.58.
 7. Thecopolymer according to claim 1 wherein x:y is 1:0.77.
 8. A method formanufacturing an organic light emitting diode display comprising:forming an electrode on a substrate; depositing an organic lightemitting layer on the electrode; depositing a photoresist on the organiclight emitting layer, the photoresist including a copolymer formed bythe process comprising: providing a first monomer represented by formula(1) and a second monomer represented by formula (2)

and forming the copolymer from the first monomer and the second monomer,where x:y is a ratio of the first monomer to the second monomer and x:yis selected from the range of x:y=1:0.1 to x:y=1:1; patterning thephotoresist into a patterned photoresist by exposing the photoresist toultraviolet light using a mask; patterning the organic light emittinglayer into a patterned organic light emitting layer using the patternedphotoresist; and stripping the patterned photoresist.
 9. The methodaccording to claim 8, wherein the ultraviolet light has a wavelength of365 nm.
 10. The method according to claim 8, wherein the photoresist ispatterned using a fluorinated solvent.
 11. The method according to claim8, wherein x:y is selected from the range of x:y=1:0.19 to x:y=1:0.77.12. A method for manufacturing an organic light emitting diode displaycomprising: forming an electrode on a substrate; depositing aphotoresist on the electrode, the photoresist including a copolymerformed by the process comprising: providing a first monomer representedby formula (1) and a second monomer represented by formula (2)

and forming the copolymer from the first monomer and the second monomer,where x:y is a ratio of the first monomer to the second monomer and x:yis selected from the range of x:y=1:0.1 to x:y=1:1;patterning thephotoresist into a patterned photoresist by exposing the photoresist toultraviolet light using a mask; depositing an organic light emittinglayer on the patterned photoresist and the electrode; and removing thepatterned photoresist and portions of the organic light emitting layeron the patterned photoresist.
 13. The method according to claim 12,wherein the ultraviolet light has a wavelength of 365 nm.
 14. The methodaccording to claim 12, wherein the photoresist is patterned using afluorinated solvent.
 15. The method according to claim 12, wherein x:yis selected from the range of x:y=1:0.19 to x:y=1:0.77.